In a medium bowl, mix together the condensed milk, peanut butter, vanilla and salt until smooth.
Fold in the Greek yogurt, milk, and cocoa powder, and beat until completely combined.
Pour the mixture into a crank freezer or electric ice cream maker and follow the manufacturer’s directions.
Pack ice cream into a quart-size lidded container. Cover with plastic wrap, pressing it onto the surface of the ice cream. Place the ice cream into the freezer and leave until fully set, about 5 to 6 hours, or overnight.